[patch 02/71] poll/select: initialize triggered field of struct poll_wqueues
From: Greg KH
Date: Fri Sep 04 2009 - 20:20:41 EST
2.6.30-stable review patch. If anyone has any objections, please let us know.
------------------
From: Guillaume Knispel <gknispel@xxxxxxxxxxxxxxxxx>
commit b2add73dbf93fd50f00564d7abc3e2b9aa9dd20c upstream.
The triggered field of struct poll_wqueues introduced in commit
5f820f648c92a5ecc771a96b3c29aa6e90013bba ("poll: allow f_op->poll to
sleep").
It was first set to 1 in pollwake() (now __pollwake() ), tested and
later set to 0 in poll_schedule_timeout(), but not initialized before.
As a result when the process needs to sleep, triggered was likely to be
non-zero even if pollwake() is not called before the first
poll_schedule_timeout(), meaning schedule_hrtimeout_range() would not be
called and an extra loop calling all ->poll() would be done.
This patch initialize triggered to 0 in poll_initwait() so the ->poll()
are not called twice before the process goes to sleep when it needs to.
Signed-off-by: Guillaume Knispel <gknispel@xxxxxxxxxxxxxxxxx>
Acked-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Acked-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
fs/select.c | 1 +
1 file changed, 1 insertion(+)
--- a/fs/select.c
+++ b/fs/select.c
@@ -110,6 +110,7 @@ void poll_initwait(struct poll_wqueues *
{
init_poll_funcptr(&pwq->pt, __pollwait);
pwq->polling_task = current;
+ pwq->triggered = 0;
pwq->error = 0;
pwq->table = NULL;
pwq->inline_index = 0;
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/